Kelton wrote a lot of stuff about SC/MC:
>
> HOWEVER, I have one lens, a 50mm f/1.4, serial number 9001XX, that
> doesn't support the *reverse* of the hypothesis, which would
> state, "All
> MC lenses show a green reflection." (Logicians: isn't this reversed
> hypothesis called "affirming the consequent"?) The lens I mention is
> clearly marked MC around the objective, yet I find no green
> reflections
> on any of the surfaces, after exhaustive viewing in a variety
> of light
> sources. I see lavender, rose, pink, but no green. Well, with
> one tiny
> caveat: if I hold this lens just right, I am able to view a
> lighter-colored ring deep within the lens. As I move the lens
> slowly in a
> strong light, I can view a 'refraction rainbow' against this lighter
> surface -- and, like any "rainbow refraction," there's a tad
> of green in
> it. But this lens does not demonstrate the obvious "green (or
> aqua) light
> bulb" reflection that I'm accustomed to seeing in other MC
> lenses, when
> examined under a strong bare bulb.
>
> I'd like to hear others verify this before I declare,
> positively, that
> "green always means multicoating but multicoating doesn't always mean
> green," but I believe I now have some evidence toward this statement.
My 50mm f1.4 exhibits identical reflections to yours and it's also marked
MC.
As a coincidence I was looking at an OM-40 in a pawn shop yesterday and it
had a 50mm f1.4, this one had "Japan" on the lens ring (no "MC") and showed
a definite green reflection (I didn't notice the other colours - I was just
using the GGR test). I believe the "Japan" versions are newer than the "MC"
versions, so I guess they changed the MC formulation as well as the
designation on at least 1 lens.
I also have a RMC (Real Multi Coated ?) Tokina 28-85 Zoom which shows bright
blue, rose & amber reflections.
Wayne Harridge
Ivanhoe, Victoria, Australia
http://www.geocities.com/Paris/Louvre/6152/
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